Method for configuring field devices

ABSTRACT

The disclosure relates to a method for configuring field devices in a process automation system wherein the field devices are connected to other automation components by means of a field bus. In order to minimize the load placed on the field bus, a copy of the current configuration of each field device is stored in a configuration tool, the appropriate set of configuration and parameter data is transmitted to each field device during initial start-up and modifications in relation to the previous copy of the configuration and parameter data are transmitted to the respective field device.

FIELD

The invention relates to a method for configuring field devices in aprocess automation system.

BACKGROUND

Modern process automation systems as used in the chemical, petroleum andother process industries employ intelligent field equipment, sensors andactuators. These field devices, as they are known, are connectedtogether and to the rest of the process automation system components viaa fieldbus system or other communications installations.

SUMMARY

The automation functions, which are essentially control loops, aredistributed across these field devices. The potential use in hazardousareas, in particular, places limits on the resources of the fielddevices for storing the configuration and parameters, and on thetransmission bandwidth of the fieldbus systems. A configuration toolhaving a central configuration database is used for configuring andparameterizing the process automation system. This configuration toolcan be used to configure the process automation functions, including theconfigurations and parameters of the field devices, before anycommunications link has been established with the field devices (offlineconfiguration). In a subsequent step, the configuration tool is thenconnected to the fieldbus, and the configurations and parameters aredownloaded to the field devices. This download process must includesynchronization with data already held in the device, for examplepreconfigured data.

The configuration is generated on the basis of device description datain order to take into account the specific properties of the fielddevices. This device description data is normally kept inmachine-readable form as a file.

Process automation systems are used for critical, continuous processes,in which the automation function can only be stopped in certainsituations. The use of resource-limited field devices on a fieldbus witha highly restricted bandwidth requires special techniques in order to beable to download changes in configuration data and parameter data to thefield devices via the fieldbus, even during normal operation, withoutstopping the automation function.

The object of the invention is to define a method for configuring fielddevices in the process automation system, wherein the loads placed onthe communications links are minimized.

This object is achieved according to the invention by the features ofclaim 1. Advantageous embodiments of the invention are given in thedependent claims.

The invention is based on a configuration tool having a centralconfiguration database, where the said configuration tool can be used toconfigure the process automation functions, including the configurationsand parameters of the field devices, before any communications link hasbeen established with the field devices. The invention is also based onthe condition that all configurations are set in the configuration tool.

The configuration tool uses copies of field-device configuration dataand parameters, which reflect the most recent download status of thefield devices. Such a copy is recorded once only for each field device.

DESCRIPTION OF THE DRAWINGS

In the following, exemplary embodiments are described in reference tothe drawings wherein:

FIG. 1 illustrates a first method of configuring field devices in aprocess automation system; and

FIG. 2 illustrates second method of configuring field devices in aprocess automation system.

DETAILED DESCRIPTION

As illustrated in FIGS. 1 and 2, configuration changes are copied by theconfiguration tool into the configuration entries and parameter entriesof the field devices in such a way as to minimize the impact on therunning process automation functions of the whole system, and also toreduce the download operations required until the new configuration inthe field devices is obtained.

Configuration changes are copied by the configuration tool into theconfiguration entries and parameter entries of the field devices in sucha way as to minimize the impact on the running process automationfunctions of the whole system, and also to reduce the downloadoperations required until the new configuration in the field devices isobtained.

To achieve this, a copy of the most recently downloaded configuration ofeach field device is initially stored in the configuration tool in aonce-only step. By this means, even field devices already integrated inthe process automation plant and in operation can subsequently beincluded in the configuration by means of said configuration tool.

Field devices being added are provided initially with the minimumconfiguration data and parameter data required for first-time start-up.This data constitutes the most recently downloaded configuration of thefield device and is consequently stored as the copy in the configurationtool.

Subsequently, configuration changes and parameter changes from theconfiguration tool are only transferred as increments to the mostrecently downloaded configuration.

The increments are generated in the configuration tool on the basis ofcopies of field-device configuration data, which reflect the most recentdownload status of the field devices. The increments are chosen here soas to minimize the impact on the process controlled by the system andalso to minimize the transmission times by changes being as small aspossible.

In detail, this is achieved as follows: initially, a copy of the currentconfiguration of each field device is stored in the configuration tool;in the next step, the difference is determined between the currentconfiguration and the most recently downloaded configuration of the samefield device; finally, the determined difference is transmitted to therespective field device for updating the configuration data andparameter data as required. These three steps are repeated recursivelyfor each new configuration.

The generated configuration may use, for implementing the sameautomation function, more configuration entries than a configurationthat does not take account of the current configuration of the fielddevices. This means, however, that the download operations required toobtain the new configuration in the field devices can be reduced, andthe impact on the process automation function of the whole system can beminimized.

By means of the method described here, changes that were made without acommunications link to the field devices (offline) can be incrementallydownloaded to the devices or synchronized with the data held in thedevices, without needing to interrupt the process automation function ofthe whole system.

According to a further feature of the invention, it is provided toassign a version ID to each copy of a configuration. This simplifiesmanagement of a large number of configurations in the configurationdatabase.

According to a further feature of the invention, it is provided that theversion IDs are managed by each field device itself, or are changedimplicitly by download operations.

According to a further feature of the invention, it is provided that theversion IDs are downloaded to the field devices with the configurationdata by the configuration tool.

In this case, it can be provided that the extent of the as-requiredupdate of the configuration data and parameter data is determined by theconfiguration tool from the version IDs and the copy of the mostrecently downloaded configuration.

In a preferred embodiment of the invention, the version IDs are graded.The grading is based on the knowledge that a device configuration for amodern, complex field device has a certain detectable granularity thatis reflected in properties of objects. In this case it is provided that,in addition to the situation where the whole configuration has changed,the change in objects is also identified if at least one property haschanged.

The extent of the as-required update of the configuration data andparameter data is determined dynamically from the grades of the versionIDs by establishing those objects whose properties have been changed.This advantageously simplifies the process of determining the requiredupdate extent.

1. A method for configuring field devices in a process automationsystem, in which the field devices are connected to other automationcomponents via a fieldbus, which makes use of a configuration tool,wherein a copy of the most recently downloaded configuration of eachfield device is stored in the configuration tool in a once-only step,and the following steps are repeated recursively: storing a copy of thecurrent configuration of each field device in the configuration tool;assigning a version ID to each stored copy; grading the version ID toidentify objects in the current configuration that include changedproperties; determining the difference between the current configurationand the most recently downloaded configuration of the same field device;and transmitting the determined difference to the respective fielddevice for updating the configuration data and parameter data asrequired.
 2. The method as claimed in claim 1, wherein at start-up theminimum set of configuration data and parameter data required for aninitial start-up is transmitted to each field device.
 3. The method asclaimed in claim 2, wherein a version ID is assigned to each copy. 4.The method as claimed in claim 1, wherein the version IDs are managed byeach field device itself and are changed implicitly by downloadoperations.
 5. The method as claimed in claim 1, wherein the version IDsare downloaded to the field devices with the configuration data by theconfiguration tool.
 6. The method as claimed in claim 1, wherein theextent of the as-required update of the configuration data and parameterdata is determined by the configuration tool from the version IDs andthe copy of the most recently downloaded configuration.
 7. The method asclaimed in claim 6, wherein the extent of the as-required update of theconfiguration data and parameter data is determined dynamically from thegrades of the version IDs.
 8. The method as claimed in claim 5, whereinthe extent of the as-required update of the configuration data andparameter data is determined by the configuration tool from the versionIDs and the copy of the most recently downloaded configuration.
 9. Amethod for configuring at least one field device in a process automationsystem, in which the at least one field device is connected to otherautomation components via a fieldbus, which makes use of a configurationtool, comprising: storing a copy of a current configuration of the atleast one field device in the configuration tool; assigning a version IDto each stored copy; grading the version ID to identify objects in thecurrent configuration that include changed properties; determining thedifference between the current configuration and a most recentlydownloaded configuration of the respective one of the at least one fielddevice; and transmitting the determined difference to the respective oneof the at least one field device for updating configuration data andparameter data as required.